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New Member

RSPAN does not put IPv6 multicast traffic into port

Hi.

There is two switches in the equation:

WS-C2960-24TT-L    12.2(55)SE5           C2960-LANBASEK9-M

 

and stack of

 

Switch Ports Model              SW Version            SW Image
------ ----- -----              ----------            ----------
     1 12    WS-C3750G-12S      12.2(55)SE8           C3750-IPSERVICESK9-M
     2 12    WS-C3750G-12S      12.2(55)SE8           C3750-IPSERVICESK9-M
*    3 24    WS-C3750G-24T      12.2(55)SE8           C3750-IPSERVICESK9-M

 

3 is a master

There is VTP domain with pruning off and RSPAN VLAN 1001

 

core#sho vlan remote-span

Remote SPAN VLANs
------------------------------------------------------------------------------
1001

 

there is RSPAN session on first:

#sho monitor session 1
Session 1
---------
Type                   : Remote Source Session
Source Ports           :
    Both               : Fa0/11
Dest RSPAN VLAN        : 1001

 

 

Port Fa0/11 is in access mode, VLAN 303

 

and on second:

core#sho monitor session 1
Session 1
---------
Type                   : Remote Destination Session
Source RSPAN VLAN      : 1001
Destination Ports      : Gi3/0/2
    Encapsulation      : Native
          Ingress      : Disabled

 

 

Problem is that i can't see any IPv6 multicast traffic (like ICMPv6 RA or such) on Gi3/0/2 which is absolutely sure there, because if i remove monitoring session on core switch and put Gi3/0/2 into trunk mode, i can see packets i need in vlan 1001:

 

# tcpdump -s0 -nnvei eth1 vlan 1001 and ip6
tcpdump: WARNING: eth1: no IPv4 address assigned
tcpdump: listening on eth1, link-type EN10MB (Ethernet), capture size 65535 bytes
14:17:37.059045 50:57:a8:f0:72:1b > 33:33:ff:00:00:01, ethertype 802.1Q (0x8100), length 90: vlan 1001, p 0, ethertype IPv6, (class 0xe0, hlim 255, next-header ICMPv6 (58) payload length: 32) 2abc:abc:1:600b::2 > ff02::1:ff00:1: [icmp6 sum ok] ICMP6, neighbor solicitation, length 32, who has 2abc:abc:1:600b::1
          source link-address option (1), length 8 (1): 50:57:a8:f0:72:1b
14:17:38.083266 50:57:a8:f0:72:1b > 33:33:ff:00:00:01, ethertype 802.1Q (0x8100), length 90: vlan 1001, p 0, ethertype IPv6, (class 0xe0, hlim 255, next-header ICMPv6 (58) payload length: 32) 2abc:abc:1:600b::2 > ff02::1:ff00:1: [icmp6 sum ok] ICMP6, neighbor solicitation, length 32, who has 2abc:abc:1:600b::1
          source link-address option (1), length 8 (1): 50:57:a8:f0:72:1b
14:17:39.107068 50:57:a8:f0:72:1b > 33:33:ff:00:00:01, ethertype 802.1Q (0x8100), length 90: vlan 1001, p 0, ethertype IPv6, (class 0xe0, hlim 255, next-header ICMPv6 (58) payload length: 32) 2abc:abc:1:600b::2 > ff02::1:ff00:1: [icmp6 sum ok] ICMP6, neighbor solicitation, length 32, who has 2abc:abc:1:600b::1
          source link-address option (1), length 8 (1): 50:57:a8:f0:72:1b

 

 

There is no such problem with usual unicast and broadcast traffic.

Any suggestions?

1 REPLY
New Member

Interestingly, i've found bug

Interestingly, i've found bug CSCsr64007 which i stubmbled upon on one of my switches during troubleshooting. The effect of this bug was that RSPAN took IPv6 multicast packets from unrelated VLANs and forwarded them into monitor port.

Looks like they have "fixed" it filtering IPv6 multicast completely.

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